1. Field of the Invention
The present invention relates to a micropore forming apparatus and micropore forming method for forming micropores in the skin of a subject by piercing the skin with microneedles.
2. Description of the Related Art
There is known art for forming micropores in the skin of a subject by piercing the skin of the subject via a microneedle tip provided with a plurality of microneedles in order to measure a predetermined component, such a glucose, present in the interstitial fluid of the subject (US2007-0233011). In the piercing apparatus used for micropore formation described in US2007-0233011, after the piercing operation has been performed, a measuring device is mounted on the pierced region, interstitial fluid is extracted from the skin, and the glucose content is then measured.
The piercing device disclosed in US2007-0233011 causes a microneedle tip to pierce the skin of the subject to form micropores therein by driving a spring-operated piston (chuck array), the leading end of which is provided with the microneedle tip that has a plurality of microneedles for piercing.
The present applicant has proposed a method for calculating (estimating) the glucose time-area under the curve of a subject using the sodium ion content of the interstitial fluid (US2011-0124998). In this method, interstitial fluid is extracted from the skin by forming micropores in the skin of the subject using a piercing device, and adhering, for a predetermined time (for example, 60 minutes or longer), an interstitial fluid collection sheet comprising a gel collection medium onto the skin where the micropores have been formed. Then, the amounts of glucose and sodium ions contained in the interstitial fluid are measured, and the glucose time-area under the curve for the subject is estimated based on the obtained measurements of glucose and sodium ions. In this case, a small amount of sweat from the skin of the subject is also collected in the collection medium, in addition to the interstitial fluid extracted from the micropores. Since this sweat also contains sodium ions, it is desirable that a large amount of interstitial fluid is extracted from the micropores in order to reduce the influence of the sweat on the measurement.